Rollup of 8 pull requests

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -259,6 +259,9 @@ pub enum AttributeKind {
     /// Represents [`#[repr]`](https://doc.rust-lang.org/stable/reference/type-layout.html#representations).
     Repr(ThinVec<(ReprAttr, Span)>),
 
+    /// Represents `#[rustc_skip_during_method_dispatch]`.
+    SkipDuringMethodDispatch { array: bool, boxed_slice: bool, span: Span },
+
     /// Represents `#[stable]`, `#[unstable]` and `#[rustc_allowed_through_unstable_modules]`.
     Stability {
         stability: Stability,

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -50,8 +50,8 @@ impl<S: Stage> SingleAttributeParser<S> for ColdParser {
     const TEMPLATE: AttributeTemplate = template!(Word);
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
-        if !args.no_args() {
-            cx.expected_no_args(args.span().unwrap_or(cx.attr_span));
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
             return None;
         }
 
@@ -67,8 +67,8 @@ pub(crate) struct NakedParser {
 impl<S: Stage> AttributeParser<S> for NakedParser {
     const ATTRIBUTES: AcceptMapping<Self, S> =
         &[(&[sym::naked], template!(Word), |this, cx, args| {
-            if !args.no_args() {
-                cx.expected_no_args(args.span().unwrap_or(cx.attr_span));
+            if let Err(span) = args.no_args() {
+                cx.expected_no_args(span);
                 return;
             }
 
@@ -175,10 +175,10 @@ impl<S: Stage> SingleAttributeParser<S> for NoMangleParser {
     const TEMPLATE: AttributeTemplate = template!(Word);
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
-        if !args.no_args() {
-            cx.expected_no_args(args.span().unwrap_or(cx.attr_span));
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
             return None;
-        };
+        }
 
         Some(AttributeKind::NoMangle(cx.attr_span))
     }

compiler/rustc_attr_parsing/src/attributes/lint_helpers.rs

@@ -14,8 +14,10 @@ impl<S: Stage> SingleAttributeParser<S> for AsPtrParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(Word);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, _args: &ArgParser<'_>) -> Option<AttributeKind> {
-        // FIXME: check that there's no args (this is currently checked elsewhere)
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
+        }
         Some(AttributeKind::AsPtr(cx.attr_span))
     }
 }
@@ -27,8 +29,10 @@ impl<S: Stage> SingleAttributeParser<S> for PubTransparentParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(Word);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, _args: &ArgParser<'_>) -> Option<AttributeKind> {
-        // FIXME: check that there's no args (this is currently checked elsewhere)
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
+        }
         Some(AttributeKind::PubTransparent(cx.attr_span))
     }
 }

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -36,6 +36,7 @@ pub(crate) mod must_use;
 pub(crate) mod repr;
 pub(crate) mod semantics;
 pub(crate) mod stability;
+pub(crate) mod traits;
 pub(crate) mod transparency;
 pub(crate) mod util;
 

compiler/rustc_attr_parsing/src/attributes/semantics.rs

@@ -13,7 +13,10 @@ impl<S: Stage> SingleAttributeParser<S> for MayDangleParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
     const TEMPLATE: AttributeTemplate = template!(Word);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, _args: &ArgParser<'_>) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
+        }
         Some(AttributeKind::MayDangle(cx.attr_span))
     }
 }

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -139,7 +139,10 @@ impl<S: Stage> SingleAttributeParser<S> for ConstStabilityIndirectParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Ignore;
     const TEMPLATE: AttributeTemplate = template!(Word);
 
-    fn convert(_cx: &mut AcceptContext<'_, '_, S>, _args: &ArgParser<'_>) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
+        }
         Some(AttributeKind::ConstStabilityIndirect)
     }
 }
@@ -361,8 +364,8 @@ pub(crate) fn parse_unstability<S: Stage>(
                 };
             }
             Some(sym::soft) => {
-                if !param.args().no_args() {
-                    cx.emit_err(session_diagnostics::SoftNoArgs { span: param.span() });
+                if let Err(span) = args.no_args() {
+                    cx.emit_err(session_diagnostics::SoftNoArgs { span });
                 }
                 is_soft = true;
             }

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -0,0 +1,54 @@
+use core::mem;
+
+use rustc_attr_data_structures::AttributeKind;
+use rustc_feature::{AttributeTemplate, template};
+use rustc_span::{Symbol, sym};
+
+use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct SkipDuringMethodDispatchParser;
+
+impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
+    const PATH: &[Symbol] = &[sym::rustc_skip_during_method_dispatch];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+
+    const TEMPLATE: AttributeTemplate = template!(List: "array, boxed_slice");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let mut array = false;
+        let mut boxed_slice = false;
+        let Some(args) = args.list() else {
+            cx.expected_list(cx.attr_span);
+            return None;
+        };
+        if args.is_empty() {
+            cx.expected_at_least_one_argument(args.span);
+            return None;
+        }
+        for arg in args.mixed() {
+            let Some(arg) = arg.meta_item() else {
+                cx.unexpected_literal(arg.span());
+                continue;
+            };
+            if let Err(span) = arg.args().no_args() {
+                cx.expected_no_args(span);
+            }
+            let path = arg.path();
+            let (key, skip): (Symbol, &mut bool) = match path.word_sym() {
+                Some(key @ sym::array) => (key, &mut array),
+                Some(key @ sym::boxed_slice) => (key, &mut boxed_slice),
+                _ => {
+                    cx.expected_specific_argument(path.span(), vec!["array", "boxed_slice"]);
+                    continue;
+                }
+            };
+            if mem::replace(skip, true) {
+                cx.duplicate_key(arg.span(), key);
+            }
+        }
+        Some(AttributeKind::SkipDuringMethodDispatch { array, boxed_slice, span: cx.attr_span })
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -26,6 +26,7 @@ use crate::attributes::semantics::MayDangleParser;
 use crate::attributes::stability::{
     BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
 };
+use crate::attributes::traits::SkipDuringMethodDispatchParser;
 use crate::attributes::transparency::TransparencyParser;
 use crate::attributes::{AttributeParser as _, Combine, Single};
 use crate::parser::{ArgParser, MetaItemParser, PathParser};
@@ -119,6 +120,7 @@ attribute_parsers!(
         Single<OptimizeParser>,
         Single<PubTransparentParser>,
         Single<RustcForceInlineParser>,
+        Single<SkipDuringMethodDispatchParser>,
         Single<TransparencyParser>,
         // tidy-alphabetical-end
     ];
@@ -325,6 +327,16 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         })
     }
 
+    pub(crate) fn expected_at_least_one_argument(&self, span: Span) -> ErrorGuaranteed {
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            attribute: self.attr_path.clone(),
+            reason: AttributeParseErrorReason::ExpectedAtLeastOneArgument,
+        })
+    }
+
     pub(crate) fn expected_specific_argument(
         &self,
         span: Span,

compiler/rustc_attr_parsing/src/parser.rs

@@ -169,9 +169,15 @@ impl<'a> ArgParser<'a> {
         }
     }
 
-    /// Asserts that there are no arguments
-    pub fn no_args(&self) -> bool {
-        matches!(self, Self::NoArgs)
+    /// Assert that there were no args.
+    /// If there were, get a span to the arguments
+    /// (to pass to [`AcceptContext::expected_no_args`](crate::context::AcceptContext::expected_no_args)).
+    pub fn no_args(&self) -> Result<(), Span> {
+        match self {
+            Self::NoArgs => Ok(()),
+            Self::List(args) => Err(args.span),
+            Self::NameValue(args) => Err(args.eq_span.to(args.value_span)),
+        }
     }
 }
 

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -496,6 +496,7 @@ pub(crate) struct NakedFunctionIncompatibleAttribute {
 pub(crate) enum AttributeParseErrorReason {
     ExpectedNoArgs,
     ExpectedStringLiteral { byte_string: Option<Span> },
+    ExpectedAtLeastOneArgument,
     ExpectedSingleArgument,
     ExpectedList,
     UnexpectedLiteral,
@@ -539,6 +540,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                 diag.span_label(self.span, "expected a single argument here");
                 diag.code(E0805);
             }
+            AttributeParseErrorReason::ExpectedAtLeastOneArgument => {
+                diag.span_label(self.span, "expected at least 1 argument here");
+            }
             AttributeParseErrorReason::ExpectedList => {
                 diag.span_label(self.span, "expected this to be a list");
             }